The present invention relates to a confocal microscope (apparatus, method, and system) for in-vivo examinations of tissue, and particularly to a confocal microscope which facilitates cryosurgical treatment of tissue being imaged by the microscope. This invention is especially suitable for providing an instrument to examine tissue having a lesion to be treated, to cryosurgically treat the lesion, and then to examine the tissue to evaluate the effectiveness of such treatment. The term tissue herein refers to naturally or surgically exposed tissue, and the term lesion refers to an abnormality in the tissue or diseased tissue.
Confocal microscopes for scanning tissue can produce microscopic images of tissue sections. Such microscopic image sections may be made in-vivo in tissue without requiring a biopsy specimen of a lesion in the tissue. An example of a confocal microscope is the xe2x80x9cVivascopexe2x80x9d manufactured by Lucid Technologies, Inc. of Henrietta, New York. Other examples of confocal microscopes are found in U.S. Pat. No. 5,788,639 and Published International Application WO96/21938. Confocal scanning microscopes are also described in Milind Rajadhyaksha et al., xe2x80x9cIn vivo Confocal Scanning Laser Microscopy of Human Skin: Melanin provides strong contrast,xe2x80x9d The Journal of Investigative Dermatology, Volume 104, No. 6, June 1995, pages 1-7, and Milind Rajadhyaksha et al., xe2x80x9cConfocal laser microscope images tissue in vivo,xe2x80x9d Laser Focus World, February 1997, pages 119-127. These confocal microscopes have confocal optics which direct light to the patient""s tissue and image the returned light. Although these confocal microscopes are useful for examination of lesions or other diseased tissue, they have no capability for facilitating cryosurgical treatment of imaged tissue. Cryosurgery involves the freezing of tissue, such as performed for treating dermal lesions, for example, lentigos (freckles), or papillomas (warts).
Accordingly, the principal object of the present invention is to provide an improved confocal microscope system which facilitates cryosurgical treatment of the tissue being imaged by the microscope.
Another object of the present invention is to provide an improved system by which a physician can confocally image tissue to assure that a lesion in the tissue is cryosurgically treated, while minimizing the damage to healthy tissue around the lesion.
Briefly described, the present invention embodies a confocal microscope for imaging tissue having a confocal imaging system with an objective lens. The tissue may represent in-vivo tissue having a lesion to be cryosurgically treated. A device for cryosurgery while viewing the tissue, via the confocal imaging system of the microscope, includes a housing with an interior cavity and two opposite ends. The objective lens is received in the interior cavity at one end of the housing. At the other end of the housing, the housing forms, or has attached thereto, a chamber which can lie adjacent to the tissue. The confocal imaging system focuses light into the tissue, and collects returned light from the tissue via the housing, to produce an image of the tissue representing a section of the tissue. A cryogenic fluid, such as liquid nitrogen, is supplied to the chamber, thereby enabling cryosurgically treatment of the imaged tissue to be carried out.
The interior cavity of the housing may have a window defining a flrst volume between the window and the objective lens, and a second volume between the window and the chamber. The first volume has an immersion liquid optically matched to the objective lens, and the second volume is approximately evacuated to form a vacuum or a partial vacuum.
The chamber further has an input port to receive the cryogenic fluid and an output port to vent the cryogenic fluid. A source of the cryogenic fluid is piped through a control value to the input port of the chamber to effect cryosurgical treatment of the imaged tissue.
The confocal microscope enables imaging of the tissue before, during and after cryosurgical treatment of the imaged tissue. Boundaries of a lesion in the tissue to be treated may thus be located in images of the tissue before treatment, and then during and after treatment, images of the same tissue may be viewed to determine the effect of the treatment of the lesion.
The present invention also embodies a method for confocally imaging tissue and facilitating cryosurgery of the tissue including the steps of: providing a housing having an interior cavity and one end coupled to the objective lens of a confocal microscope, providing a chamber coupled to the other end of the housing, supplying a cryogenic fluid to the chamber to freeze the tissue, projecting a beam through the interior cavity and the chamber into the tissue and collecting returned light from the tissue with the aid of the confocal microscope to produce signals representing an image of a section of the tissue, and providing a display of the section in accordance with the signals.
In addition, the present invention provides a system for imaging tissue including a confocal imaging system which provides images of one or more sections of in-vivo tissue, and a chamber adjacent to the tissue and coupled to the confocal imaging system through which fluid may be supplied to effect a temperature variation in the imaged tissue during imaging.
Although the present invention is described to provide cryosurgery, other fluids than a cryogenic fluid may be supplied to the chamber to effect other temperature variation of the tissue being imaged, such as a hot fluid to thaw the tissue or cause thermolysis of tissue.